Method of producing uniform density in concrete material.



C, I. NRTGII. METHoD 0F PRQDUCING UNIFORM DENSITY IN SONGRETE MATERIA@ APPLICATION FILED ILIL( 15| 1914. an

aente May 25e i915,

3 SHEETS-SHEET I.

C. L. NORTON.

METHOD OFPRODUCING UNIFORM DENSITY IN CONCRETE NIATEHTT..

APPLICATION F1LED1uLv15,1914.

Eatnte May, T915.

Patented May 25, 1915.

3 SHEETS-SHEET 3.

fmwemww.'

N0 ETON.

THOD OI-l PRODUCING UNIFORM DENSITY IN CONCRETE MATERIAL.

FILED IULY 15,1914.

APPLIc/Imre NIE CHARLES L. NORTON, OF HUDSON,

NEW IAMPSHIRE, ASSIGNR TO ASBESTOS SHINGL'E erin,

COMPANY', NASHUA, NEW HAMPSHIRE, A CDRPORATION OF NEiV YORK.

T0 aZZ whom-1725 may concern Be it known that I, CHARLES L. NORTON, a citizen of the United States, and resident of Hudson, in the county of Hillsboro and State of New Hampshire, have invented new and useful Improvements in the Method of Producing Uniform Density in Comminuted Solid Concrete'Material, of which the following is a specification. I

My invention relates to the art ofcontinnous production of concrete slabs or plates, such as typified by the machine shown and described in United States Patent No. 979,548, dated December 2T, 1910, and has for its object the improvement of the operation and the product of such machines, in respect particularly to uniformity and regularity.

`Especially, the object is to produce tinisned concrete plates or slabs ofuniform thickness, density and strength.

Since the instruments bywhich the materials composing the concrete are compressed are, of practical necessity, unvarying in their action after having been once adjusted for a given course of operation, these` improvements are addressed to the regulation of the supply ofmaterial which is afterward con` veycd to the compressing factors. Y n

An example of the materials to be treated is described. in the above mentioned United States Patent. As it is fed to, the slab or plate making machine in a dry, comminuted state, it is capable of fioiving in some measure like a liquid, provided proper conditions are preserved. And, like a liquid, this material, if made to assume columnar proportions, exerts static pressure in all directions, somewhat like a column of'liquid, although, unlike a liquid, it is compacted or com pressed in proportion to the amount of pressure sustained. `The invention herein described thus presents two aspects, one that cf a method or process, characterized by the continuous feeding, of etmminuted dry material to a conveyor under a substantially ebnstant static, self produced pressure, or,

under the static pressure, self produced in the material by the maintenance of a substantially constant columnar head over the point of delivery to the conveyor, the other that of a machine by which the above characterized process or method may be carried on. Claims for the machine are presented Specification of Letters Patent.

Fig. 2 is a plan view of' the hopper-end of the machine; Fig'. 3 is a longitudinal central.

Patented tray 25, reis.

Application led July 15, 1914. Serial No. 851,224. 5

vertical section of the hopper-end of the chine; and Fig. i is a vertical cross section of the machine at the line ii-#l of Fig. 3;

Referring to Fig.. l (and also to said United States Patent No. 979,548 for a description of a machine of the typeunder consideration), the numeral l representsa' belt conveyer which may be a single endless belt, (or a pair of conveyors placed 'end to end, as shown inthe said patent) vdriven at constant speed in the direction of the arn rows drawn adiacent to said conveyor. This conveyor l Will be referred to as the main conveyor, since another conveyer enters into the organization of the machine. 2, 2, and

3, 3, are the press rolls, which rotate in the cutter which grooves the material M, dividing it into separate plates or slabs; 5 is a Water supply device which Wets the material after it has received 'a preliminary drypressingT by the press rolls Q, 9.; G is the delivery roll, i a leveling worm which reduces the depth of the material which proceeds from the hopper A; 8 is a rotating brush, which completes the Work of reducingr the thickness of material to a uniform dimension; 9 is a side-trimmer, which trimsv the edge of the layer of'material so as to deliver a layer of uniform width to the press rolls, and 10 is a table or support over which the belt-conveyor, or main conveyer, l, passes. There is, of course, a side-trimmer Son each side of the main conveyor. On the under side of the main cenveyer l there is a ro- Istationary bridge between the belts.

terial to the second belt, which iswet. Whilethe machine of that patent has been successfully employed in the commercial manufacture of concrete plates, its eliicient behavior was conditioned on sundry nice adjustments of machine and materials, particularly in relation to the transit of material over the l machine herein depicted and described comprises sundry inventions and improvements i not essentiallyrelated to the subject matter 20 herein claimed, and these. improvements,

I which make possible the employment of a single endless main conveyer, and obviate the necessity of the stationary bridge aforesaid, with its concomitant diliiculties, are the subject of anotherI application, iled concurrently herewith, Serial No. 851,858'.

Passing now to the subject matter with which the present specification is more intimately concernedffthere 'is mounted over the receiving end of the main conveyer ahopper. A, having an open bottomclose to the surface of the mf: in conveyer, and a lateral gateway A', opening in the direction of the travel of the conveyer surface. In its preferred form, the hopper A is a cylindrical stand-pipe, which has, therefore, cirtop of the hopper.

cular crosssection, well adapted to the uniform distribution of static pressure through the mobile material contained in it. Though it is to contain solids only, this hopper A is essentially a pressure tank. The top of the hopper A is also open, and supply pipes E and G deliver comminuted material? into the Within the hopper A, there is a shaft J (Fig. 3) rotatably mounted, and armed with crossed, flat paddle blades K, K, which continually stir the ma terial and prevent it from ucaking or arching, in other words, by agitating the material the paddles K maintain it in a quasi fiuid condition, conducive to the production of liuid pressure throughout its mass, a pressure which is maintained specifically uni- .form all over the bottom of the hopper A,

by the following means.

Since the comminuted 4solid material is made to behave practically as if it were a fluid, the static pressure in the column withv in the hopper A increases indirect proper# tion to `the depth of the column. In order to maintain the desired uniform static pressure at the bottom of the hopper A, where the material is delivered to the main conveyer 1,'the column of material is kept at constant height. The preferred specific The mode of maintaining uniform and constant pressure at the bottom of the hopper to produce a continual overflow from the open top .of the hopper. To this' end, the followo arrangement of apparatus is found suitab e: An endless belt B, termed the return conveyer, is mounted on rolls b' and o", be-

l w the main conveyer, so as to catch the s rplus material, .purposely supplied and purposely removed by the worm 7, brush 8,

and trimmers v9. f The i' surplus material pushed olf the main conveyer 1 is guided to the return conveyer B b the inclined plates 11, 11, (Figs. 3 and 4 The return conveyer carries this surplus to the chiite C, which in'turn delivers the material to the bucket hoist D. The bucket hoist D dumps the materialthrough funnel l into chute G, whence it falls into the top ot' the hopper A. Meanwhile a .fresh supply of material is introduced by means of appropriate a paratus, such as the chain or bucket hoist I and pipe E. The return su ply and fresh supply together. continuous y introduce into the topof. the hopper A more material than emergesv from the bottom ogf the hopper, so that there is a continual spill'- fromthe topi'of the hopper, into the lip'- chute F, which delivers the spill to the rei turn conveyer B. The agitating paddles K preserve the column of material in the hop-` per A in a mobile.condition,'so that as it descends, the material becomes progressively more and more compacted, sustaining thererightand left pitched worm 7, which pushes.

the material sidewise off the edges of the I main conveyer 1. Then thel brush 8, which is a cylinder armed with short wooden splints, levels off the top surface of material still more, giving it a finishing out. The predetermined thickness of material being thus obtained, the side Scrapers 9, trim the band of material at itsedges, throwing this surplus off, to, be caught by the return conveyer B. Then the material is compressed further by .the dry ress rolls 2, 2, is then wetted with water alling from the dampener 5, transversely grooved by the rotating knife-frame 4, wetpressed by the press rolls 3, 3, and linally removed, in individual slabs,

each of which is slid on to a steel plate ,as it comes olf the main conveyer l! The detailsI of mechanism are illustrated in Figs. 2, 3 and 4, and require no further extended explanation, in view of the foregoing.

What I claim, and 'desire to secure by Letters Patent, is: i

1. `The method of producing a. uniformly dense layer of substantially dry comminuted material, which consists in maintaining a column of said material at constant vertical heightv'vhile laterally confining the column and causing it to descend by continuously laterally removing the material from the bottom of the confined column, and conserving in the removed layer the density acquired at the bottom of the column.

2, T he method of producing a uniformly dense layer of substantially dry comminuted material, which consists in maintaining a column of said material at constant vertical height While laterally confining' the column and causing it to descend by continuously laterally removing the material from the bottom of the confined column, and conserving in the removed layer the density acquired at the bottom ofthe column and meanwhile maintaining the fluidity Within the column by agitating the material therein.

3. The method of producing a uniformly dense layer of substantially dry comminuted material, which consists in maintaining a column of said material at constant vertical lheight and of substantially uniform horizontal cross section While laterally confining the column and causing it to descend by continuously laterally removing the material from the bottom of the confined column, and conserving in .the removed layer the density acquired at the bottom of the column.

4. The method of producing a uniformly dense layer of substantially dry comminuted material, which consists in maintaining la column of said material at constant vertical height and of substantially uniform horizon tal cross section while laterally confining thecolumn and causing it to descend by continuously laterally removing the material from the bottom of the confined column, and conserving in the removed layer the density acquired at the bottom of the column and meanwhile maintaining the fluidity Within the column by agitating the material therein. Signed by me at Boston, Massachusetts this thirteenth day of July, 1914.

CHARLES L. NORTON Witnesses ROBERT CUSHMAN, CHARLES D. WOODBERRY. 

